scholarly journals The impact of Kaluza-Klein fermions on Standard Model fermion couplings in a RS model with custodial protection

2009 ◽  
Vol 2009 (09) ◽  
pp. 076-076 ◽  
Author(s):  
Andrzej J Buras ◽  
Björn Duling ◽  
Stefania Gori
Keyword(s):  
Standard Model ◽  
Standard Model Fermion ◽  
The Impact ◽  
Kaluza Klein

scholarly journals Spin-dependence of gravity-mediated dark matter in warped extra-dimensions

2021 ◽  
Vol 81 (3) ◽  
Author(s):  
Miguel G. Folgado ◽  
Andrea Donini ◽  
Nuria Rius
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Parameter Space ◽  
Vector Boson ◽  
Link Type ◽  
The Standard Model ◽  
Linear Dilaton ◽  
Relic Abundance ◽  
The Impact ◽  
Kaluza Klein

AbstractWe study the possibility that Dark Matter (DM) particles of spin 0, 1/2 or 1 may interact gravitationally with Standard Model (SM) particles within the framework of a warped Randall–Sundrum (RS) model. Both the Dark Matter and the Standard Model particles are assumed to be confined to the infra-red (IR) brane and only interchange Kaluza–Klein excitations of the graviton and the radion (adopting the Goldberger–Wise mechanism to stabilize the size of the extra-dimension). We analyze the different DM annihilation channels and find that the presently observed Dark Matter relic abundance, $$\Omega _{\mathrm{DM}}$$ Ω DM , can be obtained within the freeze-out mechanism for DM particles of all considered spins. This extends our first work concerning scalar DM in RS scenarios (Folgado et al., in JHEP 01:161. 10.1007/JHEP01(2020)161, 2020) and put it on equal footing with our second work in which we studied DM particles of spin 0, 1/2 and 1 in the framework of the Clockwork/Linear Dilaton (CW/LD) model (Folgado et al., in JHEP 20:036. 10.1007/JHEP04(2020)036, 2020). We study the region of the model parameter space for which $$\Omega _{\mathrm{DM}}$$ Ω DM is achieved and compare it with the different experimental and theoretical bounds. We find that, for DM particles mass $$m_{\mathrm{DM}} \in [1,15]$$ m DM ∈ [ 1 , 15 ] TeV, most of the parameter space is excluded by the current constraints or will be excluded by the LHC Run III or by the LHC upgrade, the HL-LHC. The observed DM relic abundance can still be achieved for DM masses $$m_{\mathrm{DM}} \in [4,15]$$ m DM ∈ [ 4 , 15 ] TeV and $$m_{G_1} < 10$$ m G 1 < 10 TeV for scalar and vector boson Dark Matter. On the other hand, for spin 1/2 fermion Dark Matter, only a tiny region with $$m_{\mathrm{DM }} \in [4, 15]$$ m DM ∈ [ 4 , 15 ] TeV, $$m_{G_1} \in [5,10]$$ m G 1 ∈ [ 5 , 10 ] TeV and $$\Lambda > m_{G_1}$$ Λ > m G 1 is compatible with theoretical and experimental bounds. We have also studied the impact of the radion in the phenomenology, finding that it does not modify significantly the allowed region for DM particles of any spin (differently from the CW/LD case, where its impact was quite significant in the case of scalar DM). We, eventually, briefly compare results in RS with those obtained in the CW/LD model.

scholarly journals The Impact of Excited Neutrinos onνν¯→γγProcess

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
S. C. İnan ◽  
M. Köksal
Keyword(s):  
Standard Model ◽  
Ultrahigh Energy ◽  
The Standard Model ◽  
The Impact

We examine the effect of excited neutrinos on the annihilation of relic neutrinos with ultrahigh energy cosmic neutrinos for theνν¯→γγprocess. The contributions of the excited neutrinos to the neutrino-photon decoupling temperature are calculated. We see that photon-neutrino decoupling temperature can be significantly reduced below the obtained value of the Standard Model with the impact of excited neutrinos.

A Note on Licenses in the Presence of Corruption

2017 ◽  
Vol 14 (3) ◽  
Author(s):  
Amy Farmer ◽  
Fabio Méndez ◽  
Andrew Samuel
Keyword(s):  
Standard Model ◽  
Regulatory Policies ◽  
The Standard Model ◽  
The Impact

Abstract We study the effectiveness of licenses in environments with corruption. We expand the standard model so that bribery is feasible not only when licenses are granted but also when enforced or verified. This modification alters many prior results on bribery and licensing significantly. Specifically, we show that in some cases penalties for bribery at the license-granting stage complement penalties for bribery at the permit-enforcement stage. In other cases, they act as substitutes for each other. These results are especially important for often used regulatory policies in which licenses are used in conjunction with some form of subsequent license verification. Thus, our model suggests that studying the impact of bribery at the license-granting stage should not be conducted without simultaneously studying bribery at the permit verification stage.

scholarly journals The role of automatic stabilizers in business cycle: the case of indonesia

2021 ◽  
Vol 10 (2) ◽  
pp. 167-184
Author(s):  
Haryo Kuncoro
Keyword(s):  
Fiscal Policy ◽  
Standard Model ◽  
Policy Instrument ◽  
Economic Stability ◽  
Fiscal Stimulus ◽  
Quarterly Data ◽  
Discretionary Fiscal Policy ◽  
The Impact ◽  
Automatic Stabilizers

TThe use of large fiscal stimulus packages to dampen the impact of Covid-19 recently has raised concerns about the effectiveness of the discretionary fiscal policy. This paper aims at analysing the feasibility of automatic fiscal stabilisers to mitigate economic fluctuations in the case of Indonesia. Using the IMF standard model for quarterly data over the period of 2001(1) to 2019(4), we find that the role of automatic fiscal stabilisers is getting greater both in revenue and spending. This implies that the automatic fiscal stabilisers are feasible as the main fiscal policy instrument for economic stability goals in the future. However, given the existing circumstances, Indonesia has to reform economic, regulatory, and institutional ecosystems in adopting the automatic fiscal stabilisers.

scholarly journals Flavor physics: Precision as an avenue to discovery

2020 ◽  
Vol 35 (01) ◽  
pp. 1930018
Author(s):  
Diego Guadagnoli
Keyword(s):  
Cp Violation ◽  
Standard Model ◽  
Flavor Physics ◽  
Standard Model Prediction ◽  
New Physics ◽  
Effective Theory ◽  
Theory Approach ◽  
Long Distance ◽  
The Standard Model ◽  
The Impact

This paper describes the work pursued in the years 2008–2013 on improving the Standard Model prediction of selected flavor-physics observables. The latter includes: (1) [Formula: see text], that quantifies indirect CP violation in the [Formula: see text] system and (2) the very rare decay [Formula: see text], recently measured at the LHC. Concerning point (1), the paper describes our reappraisal of the long-distance contributions to [Formula: see text],[Formula: see text] that have permitted to unveil a potential tension between CP violation in the [Formula: see text]- and [Formula: see text]-system. Concerning point (2), the paper gives a detailed account of various systematic effects pointed out in Ref. 4 and affecting the Standard Model [Formula: see text] decay rate at the level of 10% — hence large enough to be potentially misinterpreted as nonstandard physics, if not properly included. The paper further describes the multifaceted importance of the [Formula: see text] decays as new physics probes, for instance how they compare with [Formula: see text]-peak observables at LEP, following the effective-theory approach of Ref. 5. Both cases (1) and (2) offer clear examples in which the pursuit of precision in Standard Model predictions offered potential avenues to discovery. Finally, this paper describes the impact of the above results on the literature, and what is the further progress to be expected on these and related observables.

scholarly journals Testing lepton flavour universality with (semi)-leptonic $$\varvec{D_{(s)}}$$ decays

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
Robert Fleischer ◽  
Ruben Jaarsma ◽  
Gabriël Koole
Keyword(s):  
Standard Model ◽  
Branching Ratios ◽  
Current Data ◽  
Leptonic Decays ◽  
Independent Analysis ◽  
The Standard Model ◽  
Model Independent ◽  
Pseudo Scalar ◽  
The Impact ◽  
Lepton Flavour

Abstract Data in B-meson decays indicate violations of lepton flavour universality, thereby raising the question about such phenomena in the charm sector. We perform a model-independent analysis of NP contributions in (semi)-leptonic decays of $$D_{(s)}$$D(s) mesons which originate from $$c \rightarrow d \bar{{\ell }} \nu _l$$c→dℓ¯νl and $$c \rightarrow s \bar{{\ell }} \nu _{\ell }$$c→sℓ¯νℓ charged-current interactions. Starting from the most general low-energy effective Hamiltonian containing four-fermion operators and the corresponding short-distance coefficients, we explore the impact of new (pseudo)-scalar, vector and tensor operators and constrain their effects through the interplay with current data. We pay special attention to the elements $$|V_{cd}|$$|Vcd| and $$|V_{cs}|$$|Vcs| of the Cabibbo–Kobayashi–Maskawa matrix and extract them from the $$D_{(s)}$$D(s) decays in the presence of possible NP decay contributions, comparing them with determinations utilizing unitarity. We find a picture in agreement with the Standard Model within the current uncertainties. Using the results from our analysis, we make also predictions for leptonic $$D_{(s)}^+ \rightarrow e^+ \nu _e$$D(s)+→e+νe modes which could be hugely enhanced with respect to their tiny Standard Model branching ratios. It will be interesting to apply our strategy at the future high-precision frontier.

SEARCHING FOR AXIONS AND OTHER EXOTICS WITH DARK MATTER DETECTORS

2010 ◽  
Vol 25 (02n03) ◽  
pp. 564-572
Author(s):  
MAXIM POSPELOV
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Cold Dark Matter ◽  
Direct Detection ◽  
Annual Modulation ◽  
The Standard Model ◽  
Detection Capabilities ◽  
The Impact ◽  
Particle Decays ◽  
O 10

I consider models of light super-weakly interacting cold dark matter, with [Formula: see text] mass, focusing on bosonic candidates such as pseudoscalars and vectors. I analyze the cosmological abundance, the γ-background created by particle decays, the impact on stellar processes due to cooling, and the direct detection capabilities in order to identify classes of models that pass all the constraints. In certain models, variants of photoelectric (or axioelectric) absorption of dark matter in direct-detection experiments can provide a sensitivity to the superweak couplings to the Standard Model which is superior to all existing indirect constraints. In all models studied, the annual modulation of the direct-detection signal is at the currently unobservable level of O(10-5).

scholarly journals GUT PRECURSORS IN SU(3)3-TYPE MODEL AND Ncolour>3

2004 ◽  
Vol 19 (21) ◽  
pp. 1615-1621
Author(s):  
N. D. TRACAS
Keyword(s):  
Standard Model ◽  
Energy Scale ◽  
Type Model ◽  
State Contribution ◽  
The Standard Model ◽  
Wide Energy ◽  
Colour Group ◽  
Gauge Couplings ◽  
Kaluza Klein

We investigate the SU (3)3 GUT model when signs of the model (precursors), due to low compactification scale, appear before the gauge couplings of the Standard Model get unified. The Kaluza–Klein state contribution seems to lead the gauge couplings to unification through a wide energy scale only in the case when the colour group is augmented to SU(4).

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